Apparatus for generating gears



G. E. MlLLHUFF APPARATUS FOR GENERATING GEARS Aug. 25, 1953 4 Sheets-Sheet 1 Filed Oct. 18, 1949 %5 y q m M m w Aug. 25, 1953 G. E. MILLHUFF APPARATUS FOR GENERATING GEARS Filed Oct. 18, 1949 4 Sheets-Sheet 2 m m w m BY gMzw/mff QM? ATTOQNE) Aug. 25, 1953 G. E. MILLHUFF APPARATUS FOR GENERATING GEARS 4 Sheets-Sheet 3 Filed Oct. 18, 1949 IN VEN TOR. aid/6 5 Mi/l/zuff euwk 3P Arron/v5 y Aug. 25, 1953 G. E. MILLHUFF APPARATUS FOR GENERATING GEARS 4 Sheets-Sheet 4 Filed Oct. 18, 1949 INVENTOR. Gale 5 MzY/buff A TTOQNE y Patented Aug. 25, 1953 APPARATUS FOR GENERATING GEARS Gale E. Millhuif, Chicago, Ill., assignor to Goodman Manufacturing Company, Chicago, III., a corporation of Illinois Application October 18, 1949, Serial No. 122,045

Claims.

This invention relates to improvements in apparatus for generating gears, and relates particularly to improvements in machines for generating a gear having varying curvilinear pitch and varying pitch radius.

In Sloane application Serial No. 762,724, filed October 11, 1946, now Patent No. 2,585,971, issued February 19, 1952, for Improvements in Gearing, there is disclosed a novel form of varying speed gearing in which the speed variations are attained by modifying the gear tooth so that the matching pinion will contact the gear teeth at varying points with respect to the tips and roots of the gear and pinion. In this form of varying speed gearing, varying speed sets of gears may be produced with round gear and pinion blanks and a concentric pinion shaped cutter having a standard tooth form. Such varying speed gearing may also be achieved with a standard pinion mounted eccentrioally and an irregularly shaped gear blank, as may be clearly understood with reference to the aforementioned Sloane application.

Such varying speed gearing may be fabricated by a gear shaping machine as shown in Hlinsky application Serial No. 711,745, filed November 22, 1946, now Patent No. 2,602,374, issued July 8, 1952, Improvements in Apparatus for Producing Varying Speed Gearing. The apparatus according to said Hlinsky application is characterized by the use of gear sectors formed on a work support for the gear blank and by a meshing gear sector on a bell crank which is rocked by a cam to advance or retard the gear blank and work support in accordance with the varying speed at which the finished pinion and gear operate. In the aforesaid Hlinsky application a weight is employed to eliminate any backlash between the gear sector of the work support and the gear sector of the bell crank, and to urge the follower of the bell crank into contact with the cam at all times.

With the foregoing considerations in mind it is a principal object of this invention to obviate the use of such gear sectors for advancing and retarding the Work support with respect to the work spindle, and to employ a pair of fixed cams for such advancing or retarding of the work support.

A further object is to afford a resilient linkage connecting the cam followers cooperating with the fixed cams, and to maintain through said resilient linkage a constant force on the cam follower employed for advancing or retarding the work support with respect to the work spindle.

Other objects and important features of the invention will be apparent from a study of the following specification taken together with the drawings, which illustrate an embodiment which the invention has assumed in practice. The invention is not intended to be limited in terms of the embodiment herein described, other embodiments being reserved, as may be defined by the scope of the claims subjoined.

In the drawings:

Figure 1 is a plan view of a portion of a gear shaping machine embodying the improvements according to the present invention;

Figure 2 is a front elevation view of a gear shaping fixture according to the present invention;

Figure 3 is a section taken along the line 33 of Figure 2 looking in the direction of the arrows, and showing details of the external cam for advancing or retarding the work support with respect to the work spindle, and an internal cam for applying a constant load to the cam follower cooperating with the external cam; and

Figure 4 is a section taken along the line 4-4 of Figure 3 looking in the direction of the arrows.

Referring now particularly to Figures 2 and 4, the fixture according to the present invention may be used in connection with the bed II) of a gear shaping machine having a hollow work spindle I I turning therein. The hollow work spindle II is provided with a cap I2 which is held in position by a plurality of socket head screws I3. The cap I2 supports a vertical spindle l4 having a hub I5 which is held to the cap I2 by bolts I6.

A cam follower support plate I? is supported on the hub I5 and is fastened thereto by screws I8, and is provided with a pair of arms I9 and 2|, see Figure 3, to provide a support for a cam follower arm 22 pivoted at 23 thereto, and to provide a support for a second cam follower arm 24 pivoted thereto as at 26. It will be apparent that the hollow spindle II, the spindle and hub I4, I5, and the support plate I1, together with the cam follower arms 22 and 24, will rotate together as a unit.

Means are provided for support of a gear blank 21 adapted to rotate with respect to the work spindle I I, and additionally to be advanced or retarded in its movement with respect to the work spindle II, in order to provide for a vary-' ing curvilinear pitch of the finished gear made from the blank 21, and to be acted upon by a pinion-shaped cutter 28 mounted on a reciprocating and rotating arbor 29 which is controlled in its movement with respect to the spindle II.

serene The details of the control of the movement of the pinion-shaped cutter 28 on the arbor 29 form no part of the present invention, and are Well known in the art. As shown in Figure 2, the pinion-shaped cutter 28 may be located eccentrically of the arbor 29 in order to provide both varying pitch radius and varying curvilinear pitch of the gear made from the gear blank ii.

The gear blank Z'l' is adapted to be mounted on a work support 3i which includes a sleeve 32 surrounding the spindle i i. The sleeve 32 is secured to the work support Si by meansof screws 33. A sleeve 35 having a slight amount of external taper is fitted around the sleeve 32. The sleeve 35 has a flange 34 provided with a milled slot 36, see also Figure 3, which is engaged by a stop 3'5 fastened to the support by a bolt 38. The flange 3d and the work support (H are bored respectively as at 39 and ll, at a plurality 'of circumferentially spaced points to receive a spring 32 which will permit a certain amount of resilient movement of the tapered sleeve 35 with respect to the sleeve 32. The sleeve 35 is provided with a key 43 held thereto by the screws shown, which is adapted to fit within a keyway of the gear blank 21. In practice, the gear blank 27! is formed with a tapered central opening and a keyway adapted to register with the key l so that the gear blank 2? may be held firmly on the tapered sleeve 35 without the possibility of rotation with respect thereto.

The work support 3! is provided with an annular ring t l held thereto by socket head screws 46, to provide a rest for the gear blank 2? on the work support 3!.

down when engaging the tapered bore of the gear blank 2'! until the gear blank Z'l rests upon the annular support ring 345. The tapered sleeve 35 is prevented from being forced off the sleeve 32 by a spanner retaining nut 45 threaded to sleeve 32. The gear blank 27 is held in position on the tapered sleeve 35 by means of a spanner nut 46 and a washer 4i which are threaded to sleeve 32.

Means are provided for advancing and retarding the movement of the gear blank 2'5 with respect to the work spindle H in accordance with the change of curvilinear pitch of the finished gear. To this end a stationary cam 58 is provided, which rests upon a support plate 49, the cam being held to the support plate 39 and properly located by means of a dowe1 i and a plurality of socket head screws 52, see Fig. 4. The support plate id, see also Figure 2, is secured to a bracket 53 which in turn is held to the table is by a bracket 5 The cam 38 and the support 69 are provided with a bushing 56 surrounding the hub l5 and having a flange 5? which rests upon the cap it.

Since the cap it! and the arm i'i rotate with the work spindle H, and since the cam ts and the support plate d9 are held in a stationary position, the support plate 59 has secured thereto an annular wear plate 58 which rests upon the cap l2. The cam 33 is also provided with a similar annular wear plate 59 which underlies the support arm ill. Likewise, since the work support 3i is adapted to rotate with respect to the arm ii, the work support 3! is similarly provided with annular wear plates ii i.

The cam 48 cooperates with means for advancing or retarding the work support with respect to the work spindle H and the arm I1, and to this end the external cam 58 is engaged by a cam roller 62 mounted at the end of the cam It will be apparent that the springs 42 will enable the sleeve 35 to be moved follower arm 22. As shown also in Figure 3, the cam follower arm 22 is connected by a link or clevis 63 which is connected by a pin 64 to the cam follower arm 22 and by a pin 66 to an arm Ei'l extending from the work support 3|, see also Figure 4. It will be seen that as long as the cam roller 62 is in engagement with the surface of the external cam 48, and the work spindle I l is turning, that the gear blank 21 will be advanced or retarded in its rotating movement with respect to the work spindle ll according to the contour of the cam 48 at any point therealong, As shown particularly with reference to Figure 3, the cam 48 is substantially kidney-shaped, and it will be apparent that the cam roller 62 in following the contour "of the cam 38 will first advance the work support 3! with respect to the work spindle II and then retard the work support 3| with respect to the work spindle I l.

Means are provided for exerting a constant pressure by the cam roller 52 against the surface of the cam 38. As shown with particular reference to Figures 2 and 4, an internal cam 68 is supported in position by an upright member 10 welded to the bracket 53. The internal cam 63 is substantially oval in shape and cooperates with a cam roller ll mounted at the end of the arm 26. The other end of the arm 24 is connected by a pin F2 to a clevised member '13 which provides a housing for a spring l4 supported on a guide rod it provided with a head H forming an abutment for one end of the spring M. The guide rod 76 is threaded into a clevis member '88 which is connected by a pin 79 to the arm 61. A closure member 8| is held to the housing 53 by a plurality of screws, not shown, and provides an abutmerit for the other end of the spring M. It will be apparent that the load in the spring M may be adjusted by threading the rod 76 into the clevis member 18.

It will be apparent from the foregoing description that the spring M in tending to elongate will exert a pull on the arm 67 and will thus, through the clevis t3, exert a pul1 on the cam follower arm 22 so that the cam roller 52 is constantly in contact with the surface of the external cam 48. The linkage including the cam follower arm 24 and the clevis i3 is such that the load in the spring 14 will be maintained at a substantially constant value to be insuring that the cam roller 62 will bear against the external cam with substantially uniform pressure.

The upright member it supports a trough 82 which also provides a protective shield for the earns 68 and 4B. The trough 82 is continuous with a downspout 83 to provide for removal of cuttings and cutting oil occasioned by the shaping operation of the gear blank 21!.

According to the present invention there has been provided a novel and useful fixture for adapting a gear shaping machine for cutting gears having varying curvilinear pitch and varying pitch radius. According to the contour of the cams employed, the fixture may also be adapted for cutting gears having varying curvilinear pitch and constant pitch radius according to whether a concentric pinion cutter is employed or whether an eccentric pinion cutter is employed.

While the invention has been described in terms of an embodiment which it has assumed in practice, it is not intended to be limited in terms of the embodiment shown nor otherwise than by the terms of the claims appended.

I claim as my invention:

1. In a machine for generating a varying speed gear, a reciprocating pinion-shaped cutter rotatably driven at constant speed during its reciprocating movement, a rotating work spindle, a support for a gear blank mounted to rotate relative to said work spindle, means for advancing or retarding the rate of feed movement of said gear blank with respect to said work spindle in accordance with the relative speed ratio at which the finished gear and its mating pinion will operate comprising a stationary cam, a cam follower cooperating therewith and connected to said gear blank support, and means for urging said cam follower against said cam at substantially uniform pressure for all positions of said work spindle and said gear blank support comprising a second stationary cam, a second cam follower cooperating therewith and connected to said gear blank support.

2. The invention as defined in claim 1 characterized by a resilient connection between said second cam follower and said gear blank support.

3. The invention as defined in claim 1 characterized by resilient means connecting one of said cam followers to said gear blank.

4. In a machine for generating a varying speed gear, a reciprocating pinion-shaped cutter rotat ably driven at constant speed during its reciprocating movement, a rotatin work spindle, a support for a gear blank mounted to rotate relative to said work spindle, means for advancing or retarding the rate of feed movement of said gear blank with respect to said work spindle in accordance with the relative speed ratio at which the finished gear and its mating pinion will operate comprising a stationary cam having an external cam surface, a cam follower cooperating therewith and connected to said gear blank support, a second stationary cam having an internal cam surface, a second cam follower cooperating with said internal cam surface and a resilient connection between one of said cam followers and said gear blank support for urging the first said cam follower against said external cam at substantially uniform pressure for all positions of said work spindle and said gear blank support.

5. In a gear shaper for generating a gear having a varying pitch radius and a varying curvilinear pitch, a reciprocating eccentrically mounted pinion-shaped cutter rotatably driven at constant speed during its reciprocating movement, a rotating work spindle, a support for a gear blank mounted to rotate relative to said work spindle, means for advancing or retarding the rate of feed movement of said gear blank with respect to said work spindle in accordance with the relative speed ratio at which the finished gear and its mating pinion will operate comprising a stationary cam, a cam follower cooperating therewith and connected to said gear blank support, and means for urging said cam follower against said cam at substantially uniform pressure for all positions of said work spindle and said gear blank support comprising a second stationary cam, a second cam follower cooperating therewith and connected to said gear blank support.

6. The invention as defined in claim 5 characterized by a resilient connection between said second cam follower and said gear blank support.

7. The invention as defined in claim 5 characterized by resilient means connecting one of said cam followers to said gear blank.

8. In a gear shaper for generating a gear having a varying pitch radius and a varying curvilinear pitch, a reciprocating eccentrically mounted pinion-shaped cutter rotatably driven at constant speed during its reciprocating movement, a rotating work spindle, a support for a gear lank mounted to rotate relative to said work spindle, means for advancing or retarding the rate of feed movement of said ear blank with respect to said work spindle in accordance with the relative speed ratio at which the finished gear and its mating pinion will operate comprising a stationary cam having an external cam surface, a cam follower cooperating therewith and connected to said gear blank support, a second stationary cam having an internal cam surface, a second cam follower cooperating with said internal cam surface and a resilient connection between one of said cam followers and said gear blank support for urging the first said cam follower against said external cam at substantially uniform pressure for all positions of said work spindle and said gear blank support.

9. In a machine for enerating a varying speed gear, a reciprocating pinion-shaped cutter rotatably driven at a constant speed during its reciprocating movement, a rotating work spindle, a support for a gear blank mounted to rotate relative to said work spindle on an axis coincident with the axis of said work spindle, means for advancing or retarding the rate of feed movement of said gear blank with respect to said work spindle in accordance with the relative speed ratio at which the finished gear and its mating pinion will operate comprising a stationary cam, a cam follower cooperating therewith and connected to said gear blank support, and resilient means for urging said cam follower against said cam at substantially uniform pressure for all positions of said work spindle and said gear blank support.

10. In a gear shaper for generating a gear having a varying pitch radius and varying curvilinear pitch a reciprocating eccentrically mounted pinion-shaped cutter rotatably driven at constant speed during its reciprocatin movement, a rotating work spindle, a support for a gear blank mounted to rotate relative to said work spindle on an axis coincident with the axis of said Work spindle, means for advancing or retarding the rate of feed movement of said gear blank with respect to said work spindle in accordance with the relative speed ratio at which the finished gear and its mating pinion will operate comprising a stationary cam, a cam follower cooperating therewith and connected to said gear blank support, and resilient means for urging said cam follower against said cam at substantially uniform pressure for all positions of said work spindle and said gear blank support.

GALE E. MILLHUFF.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,190,390 Fellows July 11, 1916 1,190,391 Fellows July 11, 1916 2,098,132 Buchholz Nov. 2, 1937 

